SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28c842adeba5e1f4ac7553c8d9877f0390daea45e275814a53586d422b72f474' 
  AND token = '4EVJAvEaU3rOkzFB/CNAP7YX/zvRr4sfiE38ZM6CxcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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