SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f8e1df80166b017d8bb57059d93cfdacc0feca77d5c6af8b92e645d53a66de' 
  AND token = 'TeT9pZ1MHh/JP+2iVa411VN6supnMHsjtitUutMejAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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