SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c318c0efc45d082e4f05ff0a876a6faf3ede030b4dd774d58ee807bd7216cc8e' 
  AND token = 'FclpXFK584URvNGi28zEgGi3A3oC63uXtXumuydNtNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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