SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f959b10f30ce991504b728b2e55d68be409af55d5add3cdcb106b9611f247f8e' 
  AND token = '/2LDdYF74zfuPO/5dxoXdxnC0Z/h46+Pxol97reQ3oA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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