SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbb870ecb2333fd73855173bf3cbbf3dd8d2560a808947082f5c4a108f421ba7' 
  AND token = 'vlNuMYc8PoZNCCrglMSbjXtu98CYikpHl3y5RLyB88w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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