SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b73074a97875b2868a8d497817f6b8fa8db5c384c82c144a7239067425a96685' 
  AND token = '81m8ez8NoQzhfmIJGvUZ3EGx5je4a/7CjPsIKjECITw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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