SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f67537d51581fa242db12f03d35401089a51235902db5f894cc57e02cec9a75' 
  AND token = 'YZFoCDuBxMwerewUfHru45uKXkAINzvvegFYirY8jMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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