SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e942b26d139b717ccdaddb957521c90fd4f215e64901bd3c8c24820590805c4c' 
  AND token = 'eC51F17i+BKgVDEGGVOJ5lAIVOpw+jwmTLuYWrfRxc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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