SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '489710b27eda142ff02f0faae61b5aaa62d4df33d6bea2f55e17e8d061c0b935' 
  AND token = 'XsprilzJfd7JUDqCn4sOQLVI6kLQaSNN3YZbdDGv0Uw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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