SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dddfcb32ef7ee6624d4ae0fe68e4d59d9983bf807075195337c438151ab373e' 
  AND token = 'QGsyWwzEHV/IpXBAUHqC+xRwdAiMKu2OULYIY2d1iDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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