SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '05446e8e59922009c10fd6b568511927509f777edc651111083c97522fc15596' 
  AND token = '82ydeUDLMayp4BWp7oX6TBiLUAkP+SEERoe4gBwBCiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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