SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d48b0f04b31c5f02c65e23b6f25bd62df984f9e8a9323507d296b79429c3ac4' 
  AND token = 'jjzae08KmB/L7cYyqo1MCdilRgy5Zp0GhLIFZgR6USU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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