SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b43a789c9d3619b33c87b31e52adcd97a3289c1c1f2241336f5bbd6c8b7fe70d' 
  AND token = 'YyVGbqsfyBEwsk/mdnL6Y/+wtRZoK4MNTHtxA+021FY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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