SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf766134ee4e47eec82ad42602497db5dbbc55dbc9f734055b75b07fdcbc645c' 
  AND token = 'LDY+KW6/gZClXQIAx+hfRMlxv9gUZbg3hQ+a+0PCwOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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