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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd78e68ffa0ca8886da0ca81f38339ee1dbf0f48cf3af7193165ef4a326f2a426' 
  AND token = 'gEiIeeGNJEqvaHGlwYHUi26B6ZSHoRm1cdhv06w7gjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}