SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '732f8637972e57027a9446785867bfcbac4b4efb74a0fa24380440025d035681' 
  AND token = 'r58NC/GXmdu1Jv+UlCzwBhOkK9UmhQsWfheosC3GOsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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