SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '474532367450992bc0ddf0ccd5178da801d306af36feaf01472061f1cf8e821c' 
  AND token = 'mEuw0XCjHcATznQGNRfE7pGjLV2g56NzKlmP4vW7kr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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