SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2d3c7a144ecdb4b1d569c209829196b71b9b8af31a9beb4242a373f99f10e59' 
  AND token = 'wkUKwiP6qFoeZfzETVrUIr3G+jqGnlJtdD3NpqPFMN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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