SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e53fc1ae23fc13ab84eeaf0d0ea22f4b1062461ff1c8ed589225312ba71ccb5c' 
  AND token = 'z11EK2EvMdXZtgmZfLJiKMhnI+uPnEEorniF2R5FUrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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