SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '917caf3f2a64cca9d604bbd0bbed9ea2988fc8cffad0f033ca2cd735bd9d19c3' 
  AND token = 'JxzAeivhjGSazON4DQMT72hOfaptSy0500mBeFRjFK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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