SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '717672582b3261333a08e58422b1d1458c57baa5035d0d37dcc8a8b63914daae' 
  AND token = '+wfZKEiUtgmhaUfSLdQTGC7V4klvXKATo3FCWvUhP9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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