SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3a1af295cb3e0eb7d034eae0dd39cd66f51370a3693acb8da8421739b5c6f8d' 
  AND token = 'PqojipXhF/AZQnxqA+JWkesJaPdoHCP0tzaZ4OkORxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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