SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77c8a96defdd6475d1e5676509097df36b973afb6860aefdea6891e14be649f4' 
  AND token = 'djHS56kYBkMG27+nTmESKhFNhTf3XXsAqb0vA6OwCwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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