SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fe7ef18f8ba76e0733a92725f722964aaf1360d336fc886dc1b5a594671ad2a' 
  AND token = '2rpWJaykdRNkm5Oav6zOEue2OYSwdNO2iRydKeQYT5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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