SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bc25daeea470fd0d19d80fafa876210335812b296f7e4cbb50b128717cfdda2' 
  AND token = 'x6rKTvsFISpTV76yxxmQAgQXHRJez4Vt6ydY+kwkIak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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