SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '555ec26b5d0cad6e665a44fafe49b27bbb2f5b650b1998cb1f97b6520bc0036d' 
  AND token = 'jfwvd3OvfY9GOvD3htDeuP7bAfUqGm8v/SDgJsTSz40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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