SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0401c54f94fec2675da338ecbc03284fd670fd2e7cbd309716707a85646c25e0' 
  AND token = 'ewlVaSFlOjm+Vt9ReUKWZgTccmshbVhRYQS8vz26PcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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