SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b223923a3354d4aa92767be7f588eb4245a0a5bf6d5a1f1362c1d806cc210b71' 
  AND token = 'ddwwN2zwc+fG9QpyzKpCsdZxXxLtGvXD/baACvXLvTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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