SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e5171ae113bb28332fbc2d69749ce05fdeeff347f36ca8daa88a40fe75557d3' 
  AND token = 'Nqgto57C9OgMlb2HIH4uhjlKNHszdkWLkiSmND3gvNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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