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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2f68b500fdc0b341d84983d448e691b7e93986f5c4bb8bbacf034f5d83cb799' 
  AND token = 'mCjkHF6zfg/TwrckbraDfL6nKZy65cHe3cS8XrBdwKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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