SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23f01e25e877526c492cee5f963b9c30b819174734b75e9a56c3cba271825e2a' 
  AND token = 'Zyt7ezoTquwxwLQhKj2RCBff7xrMbtjm67fkWSAtbiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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