SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0a5cb08948f594c097da7df1c4e949fb2505671483e013f019822f4bc9b83d5' 
  AND token = 'ZuEpL/AVSvzctRFmggm2S8tJa7AmIlpVHNLr+/Lu/qQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}