SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2aa5f5dbf1ef7c357bc5cee0477290631ec86ea61bacf654f2f770f5814efb62' 
  AND token = 'VQj8nLWYsZd2fTiZzOjOn7kJcFsGN6p1s/pM/Jwl+Hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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