SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2268f616d39e3e76c7a7dbffbc8d65f5884414174c3906d9de8acea0bede5364' 
  AND token = 'Hu3IShY/gmuqHtV2FYjE5eSsHyeqFBkMmpFmTH+2uG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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