SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4496c37dd29896b00d88ccf5ee28517b11265d836198d505b893eee17e2e2514' 
  AND token = 'DcMBWSkWWyE+CqGexmOMlwF47UE9lG/6pfOerhDliRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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