SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26c334da952ac88776271bbd3ad8a9cde3724abbb9b9db7ddd7a3dc50291dd9d' 
  AND token = 'JUMUDMTYPhfC1wYf9cIIaA/jIKndBrwMY+uYEy1C4Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}