SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd8dd2b178ab2906d83f46570c5d446f17b01c05f1dfeac983fe9edf6eb3d147' 
  AND token = 'nReFGqYYj2B6IzhcIO3jM1WwCfFtGQCVY6lQqgVvMSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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