SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '082b8c55ab7823b2c39ce679eef3fc4fa0df601a6fd9eea28b290cbda0a07939' 
  AND token = 'KCcvuq/ew5HwH67vYo7QSzoNVOU6pChOhYeqNDpOKso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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