SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a1f829f8cfd8aa9aced1c519bd786edc61aac8cac7ae82ab20353274ac4ff69' 
  AND token = 'MM+utMRPfHMtk+m2o0MhNEmEZfxOI4MYu+AFcbCkADY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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