SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd800bc1870edb6aa76fc0297c4730d512cc04a00e5a7fee48283f0deb38856d7' 
  AND token = 'm5NofzgnCeQiLi2PDoW1J/ZrAH3u0g7C6Dm0qtXz5dE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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