SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '698e0ab80216a7a1b2eb179798eef954eb0f37d014d2210ede5b755c1f545463' 
  AND token = 'UUCFJW+wN7RO5wqQ9SvbhjuGKriVljfhUd2RQpEFmlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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