SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c144f8cea952819a0d5f266656e7305e8eef35404f0fa767d42a0a5513195eb' 
  AND token = 'VVsLkPa7UYSbjlwTBfnyZwqySO/Kj+9PQUCP2ynWH5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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