SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de995d8e2dfbd0e133968e41244b46c0a2014479b00ba42f121797713ed70dbf' 
  AND token = 'Xh1vWaGAHXfgNIz/OBo1ujSYZBjQPtFiPS0gRERaBzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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