SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2742be0d857c37155299c6d2b8865ba9ef2e8b98d1513e24a1fe7a9427c7a21a' 
  AND token = 'dKk/4fHSQ41E37uDmEPNyxGsdSYo7PCO8KIJzDyRPIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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