SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fa3fa288ea1874f0da762a0aa1bbb8ffa1c2bf777133b146cb9b6a205f1e9f85' 
  AND token = 'ylo91BLfFsGQbqc+ZgmTiV9irKXhxEQVE+rgzl7+DYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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