SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da857bb79f6956568370e3ccb50143a26687f49c493d2c5cb689dcf6794f44f8' 
  AND token = 'yqrtdpQRrUAuDCvbsh+P42Z6FHw5EaGypWAtLmRHlK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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