SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b26ef670072ededb861153bfde03068a0dc7ca9a96e7397ebdf4383a88c863f4' 
  AND token = 'Cro9SGXufbnjUAXV4duSdzW8Fz0y+WiGQdbzpiSxA9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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