SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db60b8114b98755a9ceed3e3fb92278fadd100f1dd4fed2eb50cfc3202406b86' 
  AND token = '00tQe+AxGXYPMzgGsBAg+aJNcMcnAJOmtPRe82Dg2UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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