SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbc7bda6319906e5d2d48716d99c34ff6ee6aefe3f6e079a867d4e26d75a9d4b' 
  AND token = 'YVqmoMijUK08BUeFf5exe1Nr5ItA2U/P1KMw+jbYOas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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