SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f277ea134f03dae9ecf47b423cead954274814e3eff319fe98adb872685978f0' 
  AND token = 'yeO6yeEDAJbHYQ/EilFoiIFh7fCfNzumh4KkmpIuUUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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