SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb47f18b3ed358023d7696334210d5060e944d13aa817e111601920dad7500f4' 
  AND token = 'A7/i+9Wk3gsV7dfsHpQHOSjZeWs6DYFU2dZmG7hDdoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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