SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cc79506791b600bef5af42357ccdf52036111cb836bafb254ca27f76cf2e5a85' 
  AND token = 'Ntzg4W6OJat5AMOEGckQNuGbm8z5luCPAryZ0m9FLWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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