SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '230d5fa4a9755ee327eff88bfa3c0f62ea0c0c71140952f34b5de12256fab227' 
  AND token = 'iZ0/HZfSSBEUNRZ6KukzxbvlfFZZz8k6CpvuIwPOagA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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