SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdf4daee614d30005b9e5f2605e45deb7021f88937bbbbd4bdf993688a6a0d83' 
  AND token = 'Lq8nK5gUgU3mDxlYsJIAj98/ChsATREouJLrRXQv1js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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