SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8df654d25c372aa98e8e54762f73e952b63165def1f02bcf4859419f7d65deb' 
  AND token = 'T/qbXDcrhoiG0J6eVSE4p/SKbH+XaQgxnzGzEOVkBfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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