SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6a05b83cd206bfb4258af28e9d1ebe05f955473d5d5028610763d78c3ceac93f' 
  AND token = '/QCuNND42ZNu7GhsPVG+0s7zHSG/8XN8Z72zJWnNomg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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