SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'deaa6bfc632d907ff9898b6aea7bc04236cae35185e3abb68c733dd7c0664887' 
  AND token = 'bieJWtdNvXaM7GMvOC5PMkO74o1AibVIrkIbESSeZrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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