SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b662603e41792bf554be478e70f6f1317f42c40efc879c524e764aaadeb15ffd' 
  AND token = 'j7TtBbASXf9hFv0Efn/zRQ3NikrZS0fwJepzZTfEAiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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