SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbae61e80d80c0ac63a3d066668f51f09e461f3c8eb80e4f2484df5dd84c9c37' 
  AND token = 'WjDloSX9+HQgYvsjRnbKi8zQ8Gqoqh+PEq2YBalakOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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