SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '769e055bc86cbfebbcff521a318c38dcf8761c0e7929512d6988d0d4718a2187' 
  AND token = 'FGgQ3mWNmyF/Kqbz+jz+fQaDGVBLTAOHtMMglt7Qn5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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