SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c138d08f774b14247d17cdd4e865e6d9c5c29437b3b278bbfaf3a97a514e325a' 
  AND token = '0g9tNmD3HfD2gXULgXUTSu0gICuKRqkr3XIUrocbtHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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