SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89371bdccde64e7a5a972440864127740d8eddac2af33b0b17b4f855b1614fa7' 
  AND token = 'TY/JT+Sl2v2dUTr3Uhpwd0It1OmovSjNEbwcRkHbhgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}