SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2c162fff89212d594c3b97107b564eef7aa62d26f1fe65b890875c492f2a8bd2' 
  AND token = 'xn1e3KHRhy7c94ZH5UdhJ/gCL1YYQAgmOE0MgBJ0rQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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