SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a35bbf50cc136dab5320af375fb1566f191f5cc57e28501b90a41624dbdfb2fb' 
  AND token = 'xKpT4qaKI+T1zXEYwJNFHHvTjZqzMnS8TOuOm0vmf+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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