SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a76e5a86f79d953acf6ea72c9dc45ccd93c779495977155195e6101f4a0af4d' 
  AND token = 'HKj+KLFIbVgw3EfbhgUv0PcXkzDiqmuJ9yCg0/4fYZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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