SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8879d486fd98e0ef6caf509e362e8c775c704fd6126e327d2ca5738dd4ce2dc0' 
  AND token = 'BEY5JdjJMdvZlGxgOgzPSSA/iJTBWkL1qQ+ZUTji690=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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