SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a59b74056e596a63d9676802232bdc23b1bbe878764e27920846a9d5b5172a3f' 
  AND token = 'ogUXPqUEy5Ki2AZzSQD3CV/CL/+m5MygKvvaYrhSWFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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