SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '789c69b98c94872cf3960c12726778be8e234d7320bdb8fd14e163de3133945e' 
  AND token = '17njdhrw/ZWzwOhkTFnKvuAWH2CzQlPrJlREb6ZnoAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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