SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6bcb9c29d4725e0a728f705e0e7e99e3787814b562a67b45830551af256b5e7' 
  AND token = 'zfG3mnqr9uY0UVm2DCZgpbB6A79LGrUVoHjhV3bGHT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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