SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '881cb05b4339ad976c473f73012ca8e3d6acf24d906666e6e3770c29f956a589' 
  AND token = 'VtBQ9t5vjlZklYvxjvqqmhudFBz76MXhRA54n7NIM9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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