SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '937f7b17ff9d01784886114c06d126f09983e85d06a7cc8dbe529a59c153d850' 
  AND token = 'ocHp0PEUl4lYVrC0EJ4zmUEs93L18qwIIaZK3hsvZhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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