SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '855d7f5a0933616a980caa361c1d4e7a91a3b4d56aa622243e7eb586fa7ffbe7' 
  AND token = 'MF+C8rwqE2j4kwj+7K4W0LziYblIjUOcNjCcu53ITjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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