SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '212800e1bb7cd50cc6c13b42f662ba586b0d54b41b52f839f58244da816f7811' 
  AND token = 'HILSDtoquBB4hAVMHZQn/8TEQOmHW7L/D7Tz3uN8HRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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