SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4ad7da1093c69ccb87e3a7c4a3d8381cab09e9775ffb67188294bed92218f57' 
  AND token = 'NXvadG276qfqjfaTKeN98d9WZDrA9sR/EnbHtDKSHgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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