SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eff9d99a179882af9cd67e43285f26c849d55aa840e215fabd32b74e02c1f5f8' 
  AND token = 'Cgz0FZ5HsLGNr/HBvXNAJLaywDVXMTmATmCqMtvuB9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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