SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efa5a6eac644f8ac9a4725c5eeeaaf8582ecf248385b146e3d3eea372ef8d165' 
  AND token = 'd0Owv3gc6Ew/R4ta7PaTSTVJmS4dD1NrKLNuF9IVE20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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