SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4afc02db195fcfca668470e81f80984d0250fcee2430b209b553b3ade39c45a7' 
  AND token = 'iy07/rnm+tFJv07el1K8P5xJnixG8vS2phPrBAsHAg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}