SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f832304d1e74978508c40ba098b4f22105eb8b2737c7f684c0e933e6cd33128' 
  AND token = '0CuMcCk/RTxJDAxfIMriXE980mocDRZYiT1UTI80ZCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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