SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53f1a0a8361a2c595cdf19979d94026086129c96ff37d2b106a64e168162fcb5' 
  AND token = 'DlAZJB3hNfKC/0E6qKGq9T+NK3Fu/7Yt2x9obr6jzLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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