SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '571ce76d762db0e0618cf39141753d7d8e81ddc731a75ce59038d67b301fa17d' 
  AND token = 'ijZVB+kM/Hn2tLQgwloxcdvksLLJ46AFkx/j5ty9K9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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