SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7820f887700f565bb54011992a65d48f85993a76789203328a9a19eedaae7547' 
  AND token = 'TU0cRriE+i2OY0s/CGy7c5gvPKoL37Luu0Ak8E4Z46A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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