SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b35c89af2dccd8c82f11f06d649684d086c0242148e98aba7df8c044e90d618' 
  AND token = 'BE6p9C5+qyigl4t9wFQHrL/jsDI4pVI+LDfBLovXpzw=' 
  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"
    }
  }
}