SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9f3ebcb4e341d562ad54cf33fbc5732b8a8ae918fab8a88aba0da8487367b44' 
  AND token = 'AApDtgncAXubhmxVCx+nR9EOuXzRrpRk5szbtnqpqvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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