SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85bcc15aacc7f02823e6bd838f01fa7047b9ad24c662fc5bd3c3f4d306c60491' 
  AND token = 'f0ZReSt4Q2kadf4NRVIk6v8Xg1GGiZ0AOmCEo/e8mtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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