SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '102f63f5aeb6322280361d118b6287cc36c847f0aff011515cbd1500c0b146fc' 
  AND token = '5cOS3Gqx+zv3czpf3e/XJJgeCgLlyUbehuzdwU+o6RE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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