SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adf351c336265f88f72d03687570ba1cd73ec60467422c0118cb12f6b25aa2f0' 
  AND token = 'tjEuCLMsJkyw/tgOqa9rsxAaO8AjJFIUcvbfqCScTGI=' 
  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"
    }
  }
}