SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba83ec815604598eaa1313d6935095b511d8bc0752d4ee4804d2c7380b3e7b49' 
  AND token = 'mGJDYuOPebpkn48b8HYmUwFFDM0onBTBDs39DXs0hD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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