SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cceb6882b7b00d0117f5de895f8f166c35cf7292a64e31273f3a58a79a7e60bf' 
  AND token = 'B3iohct9kXOzQjOdYKcRQGtBE9MvAxiAMSbUwAa80FU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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