SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a5647db13a2a32e785ec943c996cb5a115aa2d31c966ec5ef9c93acc4d0a5b7' 
  AND token = 'qMmAxdVR0/UXBB2TdQ/hu0vfBEGF1lPckgiasar3bZE=' 
  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"
    }
  }
}