SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1cbec50d209d3df3567008c36bd5e81b312415a114445859fe5ecbeaedbf82a4' 
  AND token = 'vRiWnKGYEGHyL4qMA/OQeZ3MAf5hpdVUBOJf8oP7mzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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